Method of making a switch mechanism



1958 V c. A. WOODWARD METHOD OF MAKING A SWITCH MECHANISM Filed March 17, 1954 FIG.

v INVENTCR.

CLEME NT A.WOODWARD,

BY Mia ATTORNEY.

2,847,754 METHOD OF MAKING A SWITCH MECHANISM Clement A. Woodward, Harvard, Mass., assignor, by mesne assignments, to United-Carr Fastener Corporation, Boston, Mass., a corporation of Delaware Application March 17, 1954, Serial No. 416,889 2 Claims. (Cl. 29-411) This invention relates generally to switches, and to a a method of manufacture thereof.

In the construction of radios, phonographs, television sets, and other electronic apparatus, various selector switches are provided for changing electrical circuits during the operation of the device. Switches for this purpose commonly comprise aswitch plate of wafer having a central hub with an aperture receiving an operating shaft, and a series of contact members mounted on the wafer for contact with a circuit completing member carried by the operating shaft. Since the switch is ordinarily mounted into a panel opening, a portion of the hub is externally threaded to receive a mounting nut, and the operating shaft has a D-shaped end to receive a control knob.

Such switches are relatively expensive because of the machine work involved in forming the threaded hub and shaft, and because of the assembly work necessary.

The object of this invention is to provide a method of making a switch of this type in which all machine work is eliminated and the amount of assembly work necessary is greatly reduced.

Another object of the invention is to provide a switch blank in which a switch body having an opertured hub and an operating shaft are formed as a unitary piece of molded plastic with the operating shaft being in position to be driven into the hub aperture.

Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.

In the drawing: I

Fig. 1 is a view in side elevation, partly in section, of a switch blank embodying the features of the invention;

Fig. 2 is a view of the switch blank of Fig. 1 as seen from the right side;

Fig. 3 is a view in side elevation, partly in section, of a switch manufactured in accordance with the teachings of the invention;

Fig. 4 is a view of the switch of Fig. 3 as seen from the right side;

Fig. 5 is a view in section taken on line 4; and

Fig. 6 is a view in section taken on line 6-6 of Fig. 4.

Referring to the drawing, there is illustrated a switch blank 10 which comprises generally a switch body 12 and a switch operating shaft 14 molded as a single unit from an insulating material such as a synthetic organic plastic for example, a polyamide or a cellulose acetate butyrate resin. The switch body 12 comprises generally a wafer or plate portion 16 and a central hub 18 which protrudes a substantial distance from one side of the plate.

The plate 16, on one side of the hub, is provided with a series of apertures 20 to receive contacts 22, and on the other side of the hub is provided with a pair of spaced stop members 24 and a detent 26 disposed therebetween for a purpose to appear hereinafter.

The hub 18 has a central shaft receiving aperture 28, an externally threaded end portion 30 a shoulder portion 32 disposed between the threaded portion and the plate 55 of Fig.

which may be D-shaped to shown).

14 is disposed in alignment with is joined to the threaded end of the hub by a shearable web 34. The shaft 14 is provided with an end portion 36 of reduced size and preferably of non-circular cross-section which protrudes into the aperture 28, and also has a peripheral shoulder portion 33 disposed in spaced relation to the hub.

The switch blank 10 is preferably formed by injection 16, and an outer end 39 receive a control knob (not The operating shaft the aperture 28, and

' molding of the switch body and the operating shaft substantially simultaneously as a single unit joined by the shearable web.

In one method of completing the forming of the switch, the blank 10 may then be discharged from the mold in the usual manner and the shaft 14 is subsequently driven into the aperture, thereby shearing the connecting web 34 so that the shoulder 38 bears against the adjacent end of the hub and the reduced end portion 36 protrudes from the other end of the hub. Thereafter, to retain the shaft in assembly in the aperture a rotor plate 40 having a central aperture with side flanges 41 is assembled onto the reduced end portion 36' of the shaft and retained thereon by heading or otherwise deforming the reduced end portion. (See Fig. 6.)

The rotor plate 44 has a contact blade portion 42 disposed on one side of the shaft and an indexing blade portion 44 disposed on the opposite side of the shaft, with an embossed bump 46 disposed therein to operate in a manner to appear hereinafter.

The contacts 22 may be assembled onto the plate 16 at any convenient point in the manufacturing process, preferably after the rotor plate has been assembled. In the illustrated embodiment three contacts are mounted on the plate portion 16 and the contact blade is designed to make contact between the center contact and either outer contact.

The indexing blade portion 44 confines the rotation of the contact plate to the proper limits by engagement with the stop member 24, and the embossed bump 46 in cooperation with the detent 26 retains the contact blade in either position.

The completed switch may be mounted into an opening 48 in a panel 50 by means of the mounting nut 52 in the usual manner, and to prevent rotation of the switch in relation to the panel, the plate 16 may be provided with a forwardly projecting lug-54 to enter a positioning opening 5'6 in the panel.

In another method of completing the manufacture of the switch after injection molding the blank 16, after the plastic has partially or completely solidified, and while still in the mold the operating shaft 14 may be pushed partly or completely into the aperture 28 by moving appropriate mold portions together thereby shearing the web 34 before the blank 10 is discharged from the molding machine. In such cases the frictional engagement between the shaft and the walls of'the aperture retains the shaft therein until the rotor plate can be assembled onto the end of the shaft. This method of forming a switch or similar device is more fully described in my copending application Serial Number 416,890 filed March 17, 1 54.

The switch herein described is particularly adapted for rapid and economical manufacture, since the mechanism, not including the contacts, has been reduced from about eight separate parts to three parts, none of which require expensive machinery operations.

Although the illustrated switch shows three contacts with two possible positions, it will be understood that the number of contacts or the number of switch posi tions may be changed without departing from the scope of the invention.

Since certain other obvious modifications may be made in the device without departing from the scope of the invention, it is intended that all matter contained herein be interpreted in an illustrative and not in a liimting sense.

I claim:

1. The method of making a switch mechanism which comprises the steps of molding as a unit a switch body having a shaft receiving aperture axially extending through said body and an operating shaft in aligned relation with the aperture and joined to said body at one end of the opening by a shearable web, said operating shaft having a peripheral shoulder at a point rearwardly from the shearable web substantially equal to the length of said body, driving said shaft into the aperture, thereby shearing the web, until the peripheral shoulder abuts one end of the body with the end of said shaft protruding from the other end of the aperture in said body, and assembling means in the said end of the shaft to retain it in assembly in the opening.

2. The method of making a switch mechanism which comprises the steps of molding as a unit a switch body having a shaft receiving aperture axially extending through said body and an operating shaft in aligned relation with the aperture and joined to said body at one end of the opening by a shearable web, and having a reduced end portion projecting into the opening, said operating shaft having a peripheral shoulder at a point rearwardly from the shearable web substantially equal to the length of said body, driving said shaft into the aperture, thereby shearing the web, until the peripheral shoulder abuts one end of the body with the reduced end portion of said shaft protruding from the other end of the aperture in said body, and assembling means onto said reduced end to retain said shaft in assembly in the opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,668,105 Delaval-Crow May 1, 1928 1,755,210 Dohner Apr. 22, 1930 1,814,703 Johnson July 14, 1931 1,900,236 Hall Mar. 7, 1933 1,999,019 Hall Apr. 23, 1935 2,067,557 Allison Jan. 12, 1937 2,115,069 Hal Apr. 26, 1939 2,323,927 Brauchler July 13, 1943 2,707,324 Walther May 3, 1955 2,724,867 Smith Nov. 29, 1955 FOREIGN PATENTS 330,840 Great Britain June 19, 1930 

